In an anonymous city as dark and wet as a puddle at midnight, a vicious, brilliant killer has been dispatching people based on which of the seven deadly sins they've committed. "Seven," the creepy and shocking thriller starring Brad Pitt and Morgan Freeman, stumbles into the occasional plot hole -- the premise is one of those neat, symmetrical conceits that invite lapses of logic -- but the director, David Fincher, does a bruising job of alchemy, turning a gimmicky cop thriller into a work of spiritual horror.

Fincher's previous film was the unjustly dismissed Alien 3, a humid and bitter mood piece that worked quite well as a coda to that anguished series (at least until Alien: Resurrection). Fincher is a graduate of the MTV Film School, but unlike some of his up-from-rock-video contemporaries, he doesn't exalt the image at the expense of words or emotions. Seven has moments as chilling and forceful as anything in The Silence of the Lambs.

Screenwriter Andrew Kevin Walker does something brave: He comes up with heroic characters so clichéd they have whiskers, but he puts a spin on them by ... letting them talk. They reveal themselves not by the usual Screenwriting 101 quirks or habits (though there are some of those here too, unfortunately) but by their philosophy. Lieutenant William Somerset (Freeman), a veteran homicide cop, is about to retire after 34 years (3 + 4: one of the movie's sly "seven" references for the attentive) and has a weary, cynical view of the citizens he protects and captures; he wishes the world weren't a shithole of violence and evil, but it is, and he's long since given up on any hope of changing things. More optimistic is his new partner, Detective David Mills (Pitt), who's hot to close this weird deadly-sins case that's just opened up; a man of action, he talks too much and doesn't think enough. Walker and Fincher draw subtle parallels and differences between these men. Seven, it turns out, isn't so much about catching the killer as about how one cop's worldview is validated, to the despair of his partner.

Every director has a blind spot, and Fincher's, like so many MTV boys, is a lack of spatial clarity. We don't know where any of the settings are in relation to each other; each scene builds to a visual wallop (and also an emotional one, which is what sets Fincher apart) but never gives us our geographical bearings. That, however, may be part of Fincher's plan. Working with the outstanding cinematographer Darius Khondji, Fincher fills the wide screen with darkness; the actors' faces, barely illuminated, fade in from the void. The scenes of the detectives entering some pitch-black apartment and encountering the ugly leavings of madness have a suffocating, threatening mood of dread. Yet it's not the usual dread of such thrillers, which make you afraid that something will pop out at the heroes (nothing ever does, with one sensational exception); it's the dread associated with seeing lonely, obscure people who died in terrible pain and in terrible ways, just because a righteous madman singled them out for his wrath. The movie has some of the impact of the scene in Silence of the Lambs when the sad, heavy corpse was unveiled on the slab. It's the human body as a playpen for insanity.

Fincher uses his stars cleverly. Brad Pitt, who has always struck me as a callow marquee idol with a little charm on loan from Robert Redford, comes through with a witty portrait of a man with lots of heart and guts but not a lot of brain cells. He makes an itchy, impatient, funny hero, and the great Morgan Freeman is around to cool him down. Incapable of a less-than-stunning performance, Freeman is a generous team player, lifting his co-stars up to his level without breaking a sweat (Pitt has Freeman to thank for much of his fine work here). It's completely Freeman's show, but he doesn't carry it so much as embody its concerns. Pitt gets top billing, but we experience everything through Somerset's wise, sad eyes. Whenever the writer gives him a philosophical speech, Freeman brings it home without a scratch, lending the words gravity without pomposity. The pocket of warmth that develops between these men stands in stark contrast to the cold shadows that close in around them.

And what about the killer? The identity of the actor who plays him was supposed to be some big secret at the time, but I don't see why; this isn't really that kind of movie (if we're ever meant to think that the killer could be Somerset or Mills, there are no red-herring hints to suggest that). And the actor isn't, say, Harrison Ford or Tom Hanks -- stars that we would be shocked to find playing twisted butchers. I will say that this was the second time in 1995 that this actor (who looks and acts here like a demented Michael Stipe) has played a villain shrouded in mystery, and he plays him to eerie perfection. Near the end, the killer has a self-justifying speech that rivals Ben Kingsley's in Death and the Maiden for pure insane logic, and the actor sells it beautifully. The righteous Mills rejects the killer's rant as mania, but Somerset is too old inside to dismiss it out of hand: The world really is horrible, and innocence gets harder to find every day. What matters is how one responds and relates to life in spite of that. Seven will lure people on the strength of its sicko premise and baroque deaths (some of the clinical details will shock the unshockable), but it's as serious as they come, a moral vision of an amoral landscape.

By the end, when the final blood is drawn on scorched, infertile soil -- a battlefield of mind and soul -- the portrait of desolation is complete. "Seven" is the most disquieting and powerful Hollywood thriller in years.